More attractive to teachers, the report says, is smaller class sizes and opportunities to collaborate with colleagues, said Teri Battaglieri, executive director of the Great Lakes Center for Education Research and Practice, which helped fund the study.

This may miss the point of incentive pay. A recent New York Times article notes that the impact can be seen in better recruitment of teachers. For direct rewards, this would seem to be the substantive impact. Economically the balancing point is what is the cost of the incentive vs. that of removing an underperforming teacher? Quite likely the former would win.

Secondarily, if a good teacher can have an impact on a child’s life measured in the tens of thousands of dollars, how much is that teacher worth? The same as the teacher who is negatively impacting the child’s future economic potential? The question answers itself. the point is not the rewards but the identifying the good teachers (and the poor ones) rewarding the former and dismissing the latter.